The invention relates to a surface-mounted, fiber-optic transmitting or receiving component. In particular, the present invention relates to a surface-mounted, fiber-optic transmitting or receiving component by which a beam path between a transmitter or receiver and an optical fiber can be accurately adjusted during an assembly process. For this purpose, the transmitting or receiving component has a beam deflection device, which is also referred to as a deflection receptacle, in which two assemblies can be adjusted relative to one another and can be fixed in a desired position relative to one another during the assembly process.
In recent years, surface mounting technology (SMT) has increasingly replaced the process of fitting components with wires to conductor strip carriers. The overriding advantage of SMT is the capability to fit components on boards fully automatically, very quickly, and thus cost-effectively, and this cannot be achieved by conventional component placement methods.
Owing to the high packing density that is desirable in many optical applications, SMT is of particular importance in the field of optoelectronics. Numerous optoelectronic components are already known which are configured in accordance with the SMT concept such that they can be surface-mounted.
The fundamental difficulty with fiber-optic transmitting or receiving components is to achieve optical coupling that is as good as possible between the optical fiber and the optoelectronic transmitter or receiver, as a rule a semiconductor laser or a semiconductor photodiode.
The surface-mounted, fiber-optic transmitting or receiving components known from the prior art have an SMD mounting frame which contains external connecting pins which are connected via electrical bushings to a transmitter or receiver installed in the mounting frame, such as a semiconductor laser or a semiconductor photodiode. A beam deflection device is mounted on the mounting frame, having at least one lens, one deflection mirror and one guide tube (ferrule) which can be moved axially. Since the beam deflection device is prefabricated, its individual components are internally rigidly connected to one another at the time when it is mounted on the mounting frame. In consequence, it is no longer possible to retrospectively compensate for specific discrepancies, resulting from the manufacturing process, by adjustment. In particular, discrepancies in the position or orientation of the optical axis of the fiber at right angles to the mounting plane of the deflection receptacle are problematic in this context and can, for example, lead to poorer coupling of the radiation beam emitted from a transmitter into the optical fiber.
It is accordingly an object of the invention to provide a surface-mounted, fiber-optic transmitting or receiving component having a deflection receptacle which can be adjusted during assembly and a method for its assembly which overcome the above-mentioned disadvantages of the prior art devices and methods of this general type, in which an optical beam path between a transmitter or a receiver and the light inlet or outlet end, respectively, of an optical fiber, can be aligned precisely.
With the foregoing and other objects in view there is provided, in accordance with the invention, a surface-mounted, fiber-optic component formed of a mounting platform having a recess formed therein, a first side and a second side. A device having electrical connections and selected from the group consisting of transmitters and receivers is provided. The device is fixed on the first side of the mounting platform. A beam deflection device is mounted on the second side of the mounting platform. The beam deflection device has a first assembly with a deflection mirror and a second assembly with a fiber holding device. The first assembly and the second assembly can be adjusted relative to one another and fixed in a desired position during an assembly process. A mounting frame, is provided, for housing the mounting platform. The mounting frame has external connecting pins and electrical bushings through which the electrical connections of the device are connected to the external connecting pins of the mounting frame.
In the method according to the invention for assembling the surface-mounted, fiber-optic transmitting or receiving component, the first assembly is fixed on one side of the mounting platform. The transmitter or receiver is mounted on the other side of the mounting platform. The second assembly is placed on the first assembly and on the surface of the mounting platform. The second assembly is moved in such a way that an optical beam path is produced between a radiation beam emerging from the optical fiber and a receiver, or for a radiation beam, emerging from a transmitter and the optical fiber. The second assembly is fixed in a desired position on the mounting platform and on the first assembly, and the mounting platform is inserted into the mounting frame.
The optical beam path between the transmitter or receiver and the inlet or outlet end of the optical fiber can thus be aligned precisely during the assembly of the surface-mounted, fiber-optic transmitting or receiving component. The second assembly is not fixed on the mounting platform and on the first assembly until this precise alignment has been achieved. The assemblies and the mounting platform are preferably made of metal so that the fixing process can be carried out in a conventional manner by a welded joint.
In one preferred embodiment, the first assembly is in the form of a right-angled bracket which, and within the right angle, has a surface which runs obliquely between the limbs and on which the deflection mirror is disposed. Furthermore, the second assembly has two main surfaces which are opposite and parallel to one another, between which an optical fiber is routed in a bushing, which is parallel to the main surfaces, as far as one side surface of the first assembly. A first main surface of the second assembly is mounted on a planar surface of the mounting platform. A an inner surface of one of the limbs of the first assembly rests on the second main surface of the second assembly in such a way that the deflection mirror faces the side surface of the first assembly and hence one end of the optical fiber. Another limb of the second assembly rests at right angles on the planar surface of the mounting platform, so that the second assembly can be moved on the planar surface of the mounting platform during the assembly process, and is fixed in a desired position on the planar surface.
Furthermore, a lens, which is held on the second assembly, is preferably disposed between the bushing in the mounting platform and the deflection mirror. The lens and a section of the second assembly that holds it (i.e. a lens holding device) can in this case be disposed in a widened region of the recess. The lens may be a spherical lens, which is held by a tubular section on the second assembly.
The first assembly, the second assembly and the mounting platform are preferably made of metal and are welded to one another. More specifically, the second assembly is welded to the mounting platform and the first assembly.
Furthermore, a guide tube, in particular a ferrule, which can be moved axially is disposed in the bushing (which contains the optical fiber) of the second assembly, by which guide tube the optical fiber can be moved along its optical axis.
With regard to the fitting of the transmitter or receiver, a transparent heat sink or submount, which covers the recess, can be fitted on one side of the recess in the mounting platform. On which heat sink the transmitter or receiver is disposed by, if necessary, additional optical elements in such a way that an optical beam path can be produced between the transmitter or receiver and the optical fiber.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a surface-mounted, fiber-optic transmitting or receiving component having a deflection receptacle which can be adjusted during assembly, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.